Welcome to brain Stuff from how Stuff works dot com where smart happens. This podcast is brought to you by Audible dot com, the Internet's leading provider of spoken word entertainment. Get a free audio book download of your choice when you sign up today. Log on to audible podcast dot com slash brain Stuff today for details. I am Marshall brain with today's question. If we were to move all of the matter in the universe into one corner, how
much space would it take up. It's hard to answer this question exactly because there are some unknowns, but if you're willing to accept three assumptions, we can come up with an answer that at least sounds reasonable. The first question is how big is the universe. No one knows, but based on observations, we might guess that it's a sphere that's thirty billion light years across. That means that the whole universe contains about ten to the thirty second
power cubic light years. It's incredibly big. The next question is how much matter does the universe contain. The mass of the universe is a source of debate right now, because there's no easy way to put the universe on a scale NASA estimates that it's about ten to the sixtims for the whole thing. Other estimates give other numbers, but they're all in that same ballpark. The next question is what density do you want to assume that the mass will have once you push it all into one corner.
If you were to really do this, if you actually didn't move all of the mass of the universe into one corner, it would condense into a black hole. But let's say that you could keep it from doing that, and you were somehow able to keep all the mass evenly distributed at a density of the sun. If you are willing to accept these three assumptions, then all of the matter in the universe would fit into about one billion cubic light years, or a cube that's approximately a
thousand light years on each side. Compared to the size of the universe, that's tiny. Imagine a despec Compared to Planet Earth. The universe is an incredibly empty place. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com.